Anna V. Goropashnaya , Inigo Yoldi Bergua , M. Hoshi Sugiura , Sarah A. Rice , Kelly L. Drew , Esther E. Dupont-Versteegden , Vadim B. Fedorov
{"title":"Skeletal muscle preservation in arctic ground squirrels during hibernation season","authors":"Anna V. Goropashnaya , Inigo Yoldi Bergua , M. Hoshi Sugiura , Sarah A. Rice , Kelly L. Drew , Esther E. Dupont-Versteegden , Vadim B. Fedorov","doi":"10.1016/j.cbpa.2025.111847","DOIUrl":null,"url":null,"abstract":"<div><div>Reduced skeletal loading and inactivity leads to muscle atrophy in humans and most mammals. By contrast, hibernating mammals demonstrate limited loss of skeletal muscle mass and strength by the end of winter after being physically inactive for several months. The present study objective was to detect any signs of muscle atrophy and restoration in arctic ground squirrel (AGS) skeletal muscles during the hibernation season. Quadriceps muscles of juvenile AGS males were collected 1–2 weeks before hibernation, and at 2, 6, 10–12 and 16–22 weeks after onset of hibernation during interbout arousal when body temperature returns to euthermic level. Muscle mass, fiber cross-sectional area (CSA) and fiber type composition were determined, as well as total and ribosomal RNA content, and expression of key genes involved in protein degradation. We found that muscle mass, CSA and fiber size distribution were not different between the groups (<em>P</em> > 0.05). No difference was detected in myofiber composition between the hibernation groups compared to pre-hibernation. Total RNA and ribosomal RNA content were not significantly different between the groups during hibernation. Transcript levels of ubiquitin E3-ligase <em>FBXO32</em> (<em>Atrogin-1</em>, <em>MAF</em>bx) and autophagy related genes <em>MAP1LC3A</em> and <em>BECN1</em> were not different between the hibernation and pre-hibernation groups. However, ubiquitin E3-ligase <em>TRIM63</em> (<em>M</em>u<em>RF-1</em>) was significantly higher expressed at 2 weeks of hibernation compared to the other timepoints. These results, for the first time, show that AGS preserve muscles during hibernation season.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"304 ","pages":"Article 111847"},"PeriodicalIF":2.1000,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","FirstCategoryId":"99","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1095643325000455","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Reduced skeletal loading and inactivity leads to muscle atrophy in humans and most mammals. By contrast, hibernating mammals demonstrate limited loss of skeletal muscle mass and strength by the end of winter after being physically inactive for several months. The present study objective was to detect any signs of muscle atrophy and restoration in arctic ground squirrel (AGS) skeletal muscles during the hibernation season. Quadriceps muscles of juvenile AGS males were collected 1–2 weeks before hibernation, and at 2, 6, 10–12 and 16–22 weeks after onset of hibernation during interbout arousal when body temperature returns to euthermic level. Muscle mass, fiber cross-sectional area (CSA) and fiber type composition were determined, as well as total and ribosomal RNA content, and expression of key genes involved in protein degradation. We found that muscle mass, CSA and fiber size distribution were not different between the groups (P > 0.05). No difference was detected in myofiber composition between the hibernation groups compared to pre-hibernation. Total RNA and ribosomal RNA content were not significantly different between the groups during hibernation. Transcript levels of ubiquitin E3-ligase FBXO32 (Atrogin-1, MAFbx) and autophagy related genes MAP1LC3A and BECN1 were not different between the hibernation and pre-hibernation groups. However, ubiquitin E3-ligase TRIM63 (MuRF-1) was significantly higher expressed at 2 weeks of hibernation compared to the other timepoints. These results, for the first time, show that AGS preserve muscles during hibernation season.
期刊介绍:
Part A: Molecular & Integrative Physiology of Comparative Biochemistry and Physiology. This journal covers molecular, cellular, integrative, and ecological physiology. Topics include bioenergetics, circulation, development, excretion, ion regulation, endocrinology, neurobiology, nutrition, respiration, and thermal biology. Study on regulatory mechanisms at any level of organization such as signal transduction and cellular interaction and control of behavior are also published.